Tapered Liquid Light Guide

ABSTRACT

A catheter tip is provided according to various embodiments of the disclosure. The catheter tip may comprise a distal end, a proximal end, and tubular walls. The distal end includes a distal aperture with a distal inside diameter, and the proximal end includes a proximal aperture with a proximal inside diameter. The proximal inside diameter may be greater than the distal inside diameter. The proximal end comprises attachment means configured to couple the proximal end with a distal end of a laser catheter. The tubular walls may include at least an inside taper from the proximal end to the distal end such that the inner tubular walls generally taper from the proximal inside diameter to the distal inside diameter. Moreover, the tubular walls may be configured to direct at least a liquid medium, for example, a biocompatible solution, toward the distal aperture.

BACKGROUND

This disclosure relates in general to liquid light guides and, but notby way of limitation, to liquid light guides used in conjunction with alaser catheter among other things.

Catheters containing optical fibers transmit energy to irradiateinternal parts of the body for diagnostic and therapeutic purposes.There are many medical applications in which it is desirable to deliverenergy, such as laser energy, through an optical fiber or similarwaveguide device disposed in a body cavity for treatment or diagnosis.These include, among others, the ablation of tissue such as plaque,calcium, and tumors, the destruction of calculi, and the heating ofbleeding vessels for coagulation. Some ablation targets, such as,calcified endovascular lesions, for example, can be especially difficultto ablate. The lasers used may produce either pulsed or continuous-wavelight of wavelengths ranging from the ultra-violet to the infra-red.

BRIEF SUMMARY

A catheter tip is provided according to one embodiment. The catheter tipmay comprise a distal end, a proximal end, and tubular walls. The distalend includes a distal aperture with a distal inside diameter, and theproximal end includes a proximal aperture with a proximal insidediameter. The proximal inside diameter may be greater than the distalinside diameter. The proximal end comprises attachment means configuredto couple the proximal end with a distal end of a laser catheter. Thetubular walls may include at least an inside taper from the proximal endto the distal end such that the inner tubular walls generally taper fromthe proximal inside diameter to the distal inside diameter. Moreover,the tubular walls may be configured to direct at least a liquid medium,for example, a biocompatible solution, toward the distal aperture. Insome embodiments, the tubular walls comprise a material with an index ofrefractive approximately less than or equal to the index of refractionof the liquid medium.

A tapered support sheath is also provided according to anotherembodiment. The tapered support sheath may include a proximal endincluding a proximal aperture configured to receive a laser catheter, adistal end including a distal aperture, and an elongated tubularstructure. In some embodiments, the inside diameter of the distalaperture is less than the inside diameter of the proximal aperture. Theelongated tubular structure may include an inner lumen that extends fromthe proximal end to the distal end and may include a taper. Theelongated tubular structure may also be configured to support a lasercatheter within at least a portion of the inner lumen such that thelaser catheter directs light toward the distal aperture. In otherembodiments, the elongated tubular structure may be configured to allowa liquid medium to flow toward the distal end within the inner lumen.The tapered support sheath may also include a liquid medium infusionport at or near the proximal end of the sheath.

A device for increasing the energy density of light emanating from alaser catheter is also disclosed according to one embodiment. The devicemay include a proximal end, a distal end, an elongated tubularstructure, coupling means, directing means and concentrating means. Theelongated tubular structure may include an inner lumen and extend fromthe proximal end to the distal end. The elongated tubular structure maybe configured to allow a liquid medium to flow through the inner lumentoward the distal end. The coupling means may include means for couplingthe device with the laser catheter. The directing means may includemeans for directing light through at least a portion of the devicetoward a target. The concentrating means may include means forincreasing the energy density of the light beam exiting the devicecompared with the energy density of the light beam entering said device.

A tapered liquid light guide is disclosed according to anotherembodiment that includes a distal end with a distal aperture, a proximalend with a proximal aperture, and a body. The cross-section of theproximal aperture is greater than the cross-section of the distalaperture. The body may include an inner lumen; a portion of which istapered. At least a portion of the inner lumen includes a material withan index-of-refraction which is lower than the inner liquid medium. Theinner lumen is also configured to allow a liquid medium to flow towardthe distal end.

A tapered liquid light guide is disclosed according to anotherembodiment that includes a distal end with a distal aperture, a proximalend with a proximal aperture, and a body. The cross-section of thedistal aperture is greater than the cross-section of the proximalaperture. The body may include an inner lumen; a portion of which istapered. At least a portion of the inner lumen includes a material withan index-of-refraction which is lower than the inner liquid medium. Theinner lumen is also configured to allow a liquid medium to flow towardthe distal end.

Further areas of applicability of the present disclosure will becomeapparent from the detailed description provided hereinafter. It shouldbe understood that the detailed description and specific examples, whileindicating various embodiments, are intended for purposes ofillustration only and do not limit the scope of the disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a laser catheter system according to one embodiment.

FIG. 2 shows a tapered liquid light guide tip according to oneembodiment.

FIG. 3 shows a tapered liquid light guide tip coupled with a lasercatheter according to one embodiment.

FIG. 4 shows a liquid light guide catheter coupled with a tapered liquidlight guide tip according to one embodiment.

FIGS. 5A-5C show tapered liquid light guide tips with various attachmentmechanisms according to various embodiments.

FIG. 6 shows a tapered liquid light guide sheath according to oneembodiment.

In the appended figures, similar components and/or features may have thesame reference label. Further, various components of the same type maybe distinguished by following the reference label by a dash and a secondlabel that distinguishes among the similar components. If only the firstreference label is used in the specification, the description isapplicable to any one of the similar components having the same firstreference label irrespective of the second reference label.

DETAILED DESCRIPTION

The ensuing description provides preferred exemplary embodiment(s) only,and is not intended to limit the scope, applicability or configurationof the disclosure. Rather, the ensuing description of the preferredexemplary embodiment(s) will provide those skilled in the art with anenabling description for implementing a preferred exemplary embodiment.It should be understood that various changes may be made in the functionand arrangement of elements without departing from the spirit and scopeas set forth in the appended claims.

Embodiments described throughout this disclosure provide for tips,sheaths, catheters, and/or devices that increase the energy density of alaser catheter. Some embodiments use tapered liquid light guides thatdecrease the beam cross-section of laser light in order to increase theenergy density. Such energy density increases may be useful for ablatingstubborn lesions, occlusions, obstructions, etc. Moreover, many of theembodiments are directed to devices that may be accessories to astandard laser catheter. For example, various embodiments includedetachable and/or replaceable catheter tips and/or sheaths.

A tapered catheter tip is provided according to one embodiment. Such atapered catheter tip may be coupled with a laser catheter. The taperprovides a decrease in the laser spot size and, therefore, an increasein the energy density of laser light. Such tips, in one embodiment, maybe constructed of material with an index of refraction which is lowerthan the liquid medium on the inner lumen at the tip in order to induceinternal reflection from within the liquid core. In another embodiment,a tip may be constructed of a material that provides low lightattenuation. In some embodiments the laser catheter may provide light inthe ultraviolet range. Moreover, the tapered catheter tip may direct aliquid medium from the proximal end of the tip toward the distal end ofthe tip.

In use, a user may be performing laser ablation within patient using aliquid light guide laser catheter. In this example, the laser cathetermay operate with 308 nm UVB light and the laser catheter may use a rangeof solutions such as NaCl solution as the liquid light guide medium. Atsome point in the procedure the doctor may encounter a target that isdifficult to ablate with the laser catheter, such as, calcifiedendovascular lesions. In such a case, an increased laser density mayprovide better ablation. Accordingly, the doctor may remove the lasercatheter, attach a tapered catheter tip. The tapered catheter tipnarrows the spot size of the laser light emanating from the lasercatheter while transmitting roughly the same laser energy. The doctormay then reinsert the laser catheter and ablate the difficult targetusing the tapered tip. Following ablation, the doctor may remove the tipor continue ablation with the tapered tip.

Some embodiments provide a tapered catheter sheath. Such a cathetersheath may be an elongated tubular structure that accepts a lasercatheter through much of the elongated portion thereof. In otherembodiments the elongated tubular structure accepts a laser catheterthrough all, most of all, or a portion thereof. In some embodiments thecatheter sheath is tapered at the distal end to decrease the spot sizeof the laser light. In other embodiments the catheter sheath may includean infusion port that provides biocompatible fluid delivery through thesheath toward the distal end of the sheath. In another embodiment, asheath may be constructed of a material that provides low attenuation oflight. In some embodiments the sheath or at least a tapered portion ofthe sheath may be constructed of material with a low index of refractionin order to induce total internal reflection. In some embodiments thelaser catheter may provide light in the ultraviolet range.

FIG. 1 shows a laser catheter system 100 according to one embodiment. Alaser 130 is shown coupled with a user interface 180. In this embodimentthe user interface 180 is computer programmed to control the laser 130.The laser, for example, may be an excimer laser. The laser, for example,may also produce light in the ultraviolet range. The laser is connectedwith a catheter 170 that may be inserted into a vessel of the human body110. The laser catheter system 100 may employ one or more taperedwaveguides that guide laser light from the laser 130 through thecatheter 170 toward a target.

FIG. 2 shows a tapered liquid light guide tip 200 according to oneembodiment. The liquid light guide tip 200 includes a distal end 230 anda proximal end 220. In this embodiment both the distal end 230 and theproximal end 220 include apertures. As shown in the figure the tipincludes a tapered portion 210 between the proximal end 220 and thedistal end 230. In some embodiments, the proximal end 220 of the taperedliquid light guide tip may be coupled with a laser catheter, a liquidlight guide 200, or both.

FIG. 3 shows the proximal end 220 of a tapered liquid light guide tip200 coupled with a laser catheter 170 according to one embodiment. Onlya portion of the laser catheter 170 is shown. When coupled with a lasercatheter 170, the liquid light guide tip 200 may direct laser light witha more concentrated spot beam toward a target from the distal end 230.In doing so, the energy density of the light incident on a target fromthe laser catheter 170 through the liquid light guide tip 200 isincreased due to the decrease in spot size. The laser catheter 170 mayalso provide a biocompatible fluid that flows through the liquid lightguide tip 200 from the proximal end 220 toward the distal end 230. Inorder to decrease the spot size of the laser beam through the tip, totalinternal reflection must be maintained through the taper 210 of theliquid light guide tip 200. Total internal reflection can be maintainedwhen the biocompatible fluid has a index of refraction greater than theindex of refraction of the lining of the tubing.

The biocompatible fluid, in some embodiments, may include a salinesolution. In other embodiments the biocompatible fluid may includeMgCl₂, NaCl, CaCl, etc. In other embodiments the biocompatible fluid mayinclude a solution comprising, for example, Ca, Mg, Mn, Ni, Cl, and/orCo. In some embodiments, the biocompatible fluid may include lactatedRinger's solution. The lactated Ringer's solution, for example, may comefrom sodium chloride (NaCl), sodium lactate (NaC₃H₅O₃), calcium chloride(CaCl₂), and/or potassium chloride (KCl). Those of skill in the art willrecognize that other combinations of salts may be used. In someembodiments, magnesium chloride and lactated Ringer's solution have goodbiocompatibility (e.g., low toxicity) as well as good light transmissioncharacteristics at the 308 nm wavelength. The biocompatible fluid may betailored to the wavelength of light produced by the laser. For example,waveguides including a biocompatible fluid of approximately 15% toapproximately 60% w/w CaCl₂ transmit light well in the infrared, butonly partially in the ultraviolet region. Also, such waveguidesgenerally do not transmit well below 250 nm. There are many types ofbiocompatible fluids that may be used without limitation. Moreover,embodiments described herein are not limited to specific biocompatiblefluid.

The body and/or walls of the tapered liquid light guide tip 200 maycomprise any low index material without limitation. For example, amaterial with an index or refraction below the index of refraction ofwater, approximately 1.4 at the 308 nm wavelength. These materials mayinclude, for example, Teflon AF2400 tubing made by DuPont. In otherembodiments, the walls may include any fluoropolymer, such as, forexample, Hyflon® PFA or MFA, FEP, KEL-F, Teflon PFA, Tefzel, Fluon,Tedlar, ECTFE, PVDF, PCTFE, FFKM, Kalrez, Viton, Krytox, and 3M THV-500.Polyethylene, PVC, polycarbonate and/or other plastics may be used insome embodiments.

The tapered liquid light guide tip 200 may include portions without ataper. For example, as shown in FIG. 2 the tip 200 may include aextended portion 250 near the proximal end and/or a extended portion 240near the distal end. While the extended portion 250 and/or the distalaperture is shown with a circular cross section, any shape may be used.For example, the cross section may be oval or polygon shaped. Moreover,in another embodiment the distal end may taper directly to the distalaperture 230 without a substantially extended portion. In anotherembodiment, the tip may be substantially cone shaped. In such anembodiment, the tip may have substantially no extended portions.

FIG. 4 shows a liquid light guide catheter 210 coupled with a taperedliquid light guide tip 200 according to one embodiment. The liquid lightguide catheter 210 also includes an infusion port 420 for introducing abiocompatible material into the laser catheter 210. The biocompatiblematerial may act as a light guide within the laser catheter thatchannels light from the proximal end through toward the distal end. Thetapered liquid light guide tip 200 includes a tapered portion 210.

FIGS. 5A-5C show tapered liquid light guide tips with various attachmentmechanisms according to various embodiments. FIG. 5A shows an attachmentmechanism such that a ring 510 on the inside of the tip catches a groveon the catheter according to one embodiment. In some embodiments, atleast a portion or all of the attachment mechanism comprises ashape-memory material that shrinks when heated to about the bodytemperature. Shrinking may more tightly secure the tip to the lasercatheter when used within a body. In FIG. 5B a ring 520 is on theexterior of the laser catheter and the grove is on the interior of thetip 200 according to another embodiment. FIG. 5C shows the tip withthreads 540 on the interior and the laser catheter with threads 530 onthe exterior. Of course, the threads may be on the exterior of the tipand the interior of the laser catheter according to another embodiment.Various other attachment mechanisms may also be used without deviatingfrom the spirit and scope of this disclosure. For example, clips,detents, rings, washers, pins, bushings, o-rings, etc., may be used aspart of the attachment mechanism. In some embodiments, the taperedliquid light guide tip may be attached using an X-Ray contrast medium, asticky material or any adhesive.

FIG. 6 shows a tapered liquid light guide sheath 600 according toanother embodiment. The liquid light guide sheath 600 may include anelongated tubular body 610, a tapered portion 615, a distal aperture, aninner lumen, and an infusion port 420. The infusion port 640 includes acatheter port 660 that receives a laser catheter 170 or other lightchanneling device. The catheter port is configured to allow a catheter,such as a laser catheter, to be fed into the inner lumen of the sheath600. The sheath 600 may also include a fluid port 670 that may becoupled, for example, with a biocompatible fluid delivery device. Thefluid port 670 may receive biocompatible fluid that flows through theinner lumen of the sheath 600. The biocompatible fluid may be used as alight guide within portions of the sheath. In some embodiments, theliquid light guide sheath may include a distal extended portion 620,while in other embodiments the sheath tapers substantially directly tothe distal aperture.

The tapered liquid light guide sheath 600 may be used to direct laserlight from a catheter and biocompatible fluid toward a target. The lasercatheter 170 may slide within the inner lumen from the infusion port 420toward the distal end. Portions of the sheath 600 may act as a liquidlight guide directing light from the laser catheter through a distalaperture toward a target. Accordingly, in some embodiments, portions orsome portions of the tapered liquid light guide sheath 600 may comprisea low index material and/or a low attenuation material. The type ofmaterial chosen as well as the type of biocompatible fluid used withinthe light guide may be chosen based on the wavelength of light producedby the laser catheter.

Specific details are given in the above description to provide athorough understanding of the embodiments. However, it is understoodthat the embodiments may be practiced without these specific details.For example, circuits, structures, and/or components may be shown inblock diagrams in order not to obscure the embodiments in unnecessarydetail. In other instances, well-known circuits, processes, algorithms,structures, components, and techniques may be shown without unnecessarydetail in order to avoid obscuring the embodiments.

While the principles of the disclosure have been described above inconnection with specific apparatuses and methods this description ismade only by way of example and not as limitation on the scope of thedisclosure.

1. A catheter tip comprising: a distal end including a distal aperturewith a distal inside diameter; a proximal end including a proximalaperture with a proximal inside diameter, wherein the proximal insidediameter is greater than the distal inside diameter, and wherein theproximal end comprises attachment means to couple said proximal end witha distal end of a laser catheter; and tubular walls including at leastan inside taper from the proximal end to the distal end such that theinner tubular walls generally taper from the proximal inside diameter tothe distal inside diameter, wherein the tubular walls are configured todirect at least a liquid medium toward the distal aperture.
 2. Thecatheter tip according to claim 1, wherein the liquid medium comprises abiocompatible solution.
 3. The catheter tip according to claim 1,wherein the tubular walls comprise a material with an index ofrefractive approximately less than or equal to the index of refractionof the liquid medium.
 4. The catheter tip according to claim 1, whereinthe liquid medium comprises a salt solution.
 5. The catheter tipaccording to claim 1, wherein the liquid medium comprises a solutioncomprising a salt selected from the group consisting of MgCl₂, NaCl, andCaCl.
 6. The catheter tip according to claim 1, wherein said attachmentmeans further comprises an attachment mechanism selected from the groupconsisting of: one or more threads, one or more detents, and one or moreridges.
 7. The catheter tip according to claim 1, wherein at least aportion of the proximal end of the catheter tip comprises shape-memorymaterial.
 8. A tapered support sheath comprising: a proximal endincluding a proximal aperture configured to receive a laser catheter; adistal end including a distal aperture, wherein the inside diameter ofthe distal aperture is less than the inside diameter of the proximalaperture; and an elongated tubular structure including an inner lumenand extending from the proximal end to the distal end, wherein theelongated tubular structure is configured to support a laser catheterwithin the inner lumen such that the laser catheter directs light towardthe distal aperture, wherein the elongated tubular structure isconfigured to allow a liquid medium to flow toward the distal end withinthe inner lumen, and wherein at least a portion of the inner lumenincludes a taper.
 9. The tapered support sheath according to claim 8,further comprising a liquid medium infusion port at or near the proximalend.
 10. The tapered support sheath according to claim 8, wherein theliquid medium comprises a biocompatible solution.
 11. The taperedsupport sheath according to claim 8, wherein the liquid medium comprisesa solution comprising a salt selected from the group consisting ofMgCl₂, NaCl and CaCl.
 12. The tapered support sheath according to claim8, wherein the liquid medium comprises a salt solution.
 13. The taperedsupport sheath according to claim 8, wherein at least a portion of theinner lumen taper is approximately near the distal end.
 14. A device forincreasing the energy density of light emanating from a laser catheter,the device comprising: a proximal end; a distal end; an elongatedtubular structure including an inner lumen and extending from theproximal end to the distal end, and configured to allow a liquid mediumto flow through the inner lumen toward the distal end; coupling meansfor coupling the device with the laser catheter; directing means fordirecting light through at least a portion of the device toward atarget; and concentrating means for increasing the energy density of thelight beam exiting the device compared with the energy density of thelight beam entering said device.
 15. The device according to claim 14,wherein the coupling means includes an attachment mechanism.
 16. Thedevice according to claim 14, wherein the coupling means includesplacing the laser catheter within the device.
 17. The device accordingto claim 14, wherein the concentrating means comprises a taper in thephysical structure of the device, wherein the taper substantiallyinternally reflects light toward an exit aperture at the distal end. 18.The device according to claim 14, wherein the directing means includes aliquid medium.
 19. The device according to claim 14, wherein theelongated tubular structure surrounds a substantial portion of the lasercatheter.
 20. The device according to claim 14, wherein the couplingmeans comprises attaching the proximal end of the device with the distalend of the laser catheter.
 21. The device according to claim 14, whereinthe coupling means comprises placing at least the distal end of thelaser catheter within the elongated tubular structure.
 22. A taperedliquid light guide comprising: a distal end with a distal aperture; aproximal end with a proximal aperture such that the cross-section of theproximal aperture is greater than the cross-section of the distalaperture; and a body including an inner lumen, wherein at least aportion of the inner lumen is tapered, at least a portion of the innerlumen comprises a low index of refraction material, and the inner lumenconfigured to allow a liquid medium to flow toward the distal end.